I don't care for Quest either. The ranch I worked at starting useing it when it first came out. I thought the horses all showed symptoms, rough coat, no shine, of having worms even tho they wormed with it as the directions stated.
Funny, IMO, these people used it because it cost more...they're thinking, I think, is if it cost more it must be good.
Becky
Hey, I just saw your post about the wormers. I use daily strongid and then ivermectin every 6 months. So far, no problems. I've only had one horse colic after a worming and it was a horse that was basically given to me (he was pretty useless). Well, as soon as I got him home, I wormed him, he colicked the next day, then dumped a big bot load. It was DISGUSTING. Probably the first time that horse had been wormed in years. Your horse must just be sensitive to that particular wormer. I have a bunch of horse health textbooks, I'll see if I can find anything pertaining to colic after worming that doesn't have anything to do with worm load.